US8279638B2ActiveUtilityA1
Output regulation circuit of a power converter without current sensing loss and method thereof
Est. expiryJul 26, 2027(~1 yrs left)· nominal 20-yr term from priority
Inventors:Chein-Kuo Hsu
H02M 1/0009H02M 3/33507
48
PatentIndex Score
8
Cited by
2
References
23
Claims
Abstract
An output regulation circuit of a power converter without current sensing loss includes a transforming circuit to receive a proportional voltage from the primary winding of the power converter during the on-time period of the power switch. The first proportional voltage is transformed to a charging current signal to charge an energy storage device. Thus, the circuit controls the power switch according to a voltage limited signal of the energy storage device.
Claims
exact text as granted — not AI-modified1. A method for output regulation of a power converter, the power converter including a power switch, comprising the following steps:
obtaining a first divided voltage divided from an input voltage from a primary winding of the power converter, during an on-time period of the power switch of the power converter;
transforming the first divided voltage to a first current;
mirroring the first current to a charging current signal;
charging an energy storage device by the charging current signal;
comparing a voltage limited signal of the energy storage device with a reference voltage; and
resetting a switch signal when the voltage limited signal is greater than the reference voltage to control the power switch of the power converter without sensing resistors, which is adapted to directly sense a switch current of the power switch, and current sensing loss
wherein a flip-flop resets the switch signal when the voltage limited signal is greater than the reference voltage to control the power switch directly of the power converter, and the flip-flop includes a D-input terminal, a clock-input terminal, a reset-input terminal and an output terminal, the clock-input terminal is connected to an oscillation circuit, the D-input terminal is connected to an auxiliary winding of the power converter, the reset-input terminal is connected to an output terminal of a comparator, which utilized to compare the voltage limited signal and the reference voltage, and the output terminal is connected to the power switch to reset the switch signal.
2. The method of claim 1 , wherein the voltage limited signal of the energy storage device during the on-time period of the power switch is according to following equation:
Δ
V
L
-
on
=
x
×
V
IN
×
A
C
×
T
on
R
x
wherein
x is current mirror transfer ratio;
C is capacitance of the energy storage device;
V IN is an input voltage of the power converter;
A is a divided ratio of the first divided voltage;
T on is time of the power converter during the on-time period; and
Rx is a voltage to current conversion ratio.
3. The method of claim 1 , wherein the voltage limited signal in the energy storage device is proportional to the switch current of the power switch.
4. The method of claim 1 , further comprising the steps of:
obtaining a second voltage divided from an output voltage of the power converter, during an off-time period of the power switch of the power converter;
transforming the second divided voltage to a second current;
mirroring the second current to a discharging current signal;
discharging the energy storage device by the discharging current signal;
comparing the voltage limited signal of the energy storage device with the reference voltage; and
resetting a second switch signal when the voltage limited signal is greater than the reference voltage to control the power switch of the power converter without sensing resistors, which is adapted to directly sense the switch current of the power switch, and current sensing loss.
5. The method of claim 4 , wherein the flip-flop resets the second switch signal when the voltage limited signal is greater than the reference voltage to control the power switch directly of the power converter.
6. The method of claim 5 , wherein the flip-flop further includes a second output terminal and the second output terminal is connected to the power switch to reset the second switch signal.
7. The method of claim 4 , wherein the voltage limited signal of energy storage device during the off-time period of the power switch is according to following equation:
Δ
V
L
-
off
=
y
×
V
O
×
B
C
×
T
off
R
y
×
N
x
wherein
y is current mirror transfer ratio;
C is capacitance of the energy storage device;
V O is an output voltage of the power converter;
B is a divided ratio the second divided voltage;
T off is time of the power converter during the off-time period;
Nx is a turns ratio of the auxiliary winding and the secondary winding; and
R y is a voltage to current conversion ratio.
8. The method of claim 4 , wherein the voltage limited signal in the energy storage device is proportional to the output voltage of the power converter.
9. A method for output regulation of a power converter, the power converter including a power switch, comprising the following steps:
obtaining a second divided voltage divided from an output voltage from a primary winding of the power converter, during an off-time period of the power switch of the power converter;
transforming the second divided voltage to a second current;
mirroring the second current to a discharging current signal;
discharging an energy storage device by the discharging current signal;
comparing a voltage limited signal of the energy storage device with a reference voltage; and
resetting a switch signal when the voltage limited signal is greater than the reference voltage to control the power switch of the power converter without sensing resistors, which is adapted to directly sense a switch current of the power switch, and current sensing loss;
wherein a flip-flop resets the switch signal when the voltage limited signal is greater than the reference voltage to control the power switch directly of the power converter, the flip-flop includes a D-input terminal, a clock-input terminal, a reset-input terminal and an output terminal, the clock-input terminal is connected to an oscillation circuit, the D-input terminal is connected to an auxiliary winding of the power converter, the reset-input terminal is connected to an output terminal of a comparator, which utilized to compare the voltage limited signal and the reference voltage, and the output terminal is connected to the power switch to reset the switch signal.
10. The method of claim 9 , wherein the voltage limited signal of energy storage device during the off-time period of the power switch is according to following equation:
Δ
V
L
-
off
=
y
×
V
O
×
B
C
×
T
off
R
y
×
N
x
wherein
y is current mirror transfer ratio;
C is capacitance of the energy storage device;
V O is an output voltage of the power converter;
B is a divided ratio the second divided voltage;
T off is time of the power converter during the off-time period;
Nx is a turns ratio of the auxiliary winding and the secondary winding; and
R y is a voltage to current conversion ratio.
11. A output regulation circuit of a power converter, the power converter including a primary winding, a secondary winding, an auxiliary winding and a power switch, comprising:
a first transforming circuit, receiving a first divided voltage from the primary winding of the power converter during an on-time period of the power switch, and transforming the first proportional voltage to a charging current signal;
an energy storage device, charged by the charging current signal;
a comparator, comparing a voltage limited signal of the energy storage device with a reference voltage; and
a flip-flop, including a D-input terminal, a clock-input terminal, a reset-input terminal and an output terminal, the clock-input terminal is connected to an oscillation circuit, the D-input terminal is connected to the auxiliary winding of the power converter, the reset-input terminal is connected to an output terminal of the comparator, and the output terminal is connected to the power switch to reset a switch signal when the voltage limited signal is greater than the reference voltage to directly control the power switch of the power converter without sensing resistors, which is adapted to directly sense a switch current of the power switch, and current sensing loss;
wherein the voltage limited signal is proportional to switch current of the power switch.
12. The circuit of claim 11 , wherein the first transforming circuit comprises:
a first voltage-current converter, transforming the first divided voltage to a first current; and
a first current mirror circuit, mirroring the first current to the charging current signal before charging the energy storage device.
13. The circuit of claim 12 , the voltage limited signal of the energy storage device during the on-time period of the power switch is according to following equation:
Δ
V
L
-
on
=
x
×
V
IN
×
A
C
×
T
on
R
x
wherein
x is current mirror transfer ratio;
C is capacitance of the energy storage device;
V bus is an input voltage of the power converter;
A is a divided ratio of the first divided voltage;
T on is time of the power converter during the on-time period; and
Rx is a voltage to current conversion ratio.
14. The circuit of claim 11 , wherein the energy storage device is an electric capacity.
15. The circuit of claim 11 , wherein the energy storage device is an inductance.
16. The circuit of claim 11 , further comprising:
a second transforming circuit, receiving a second divided voltage from the auxiliary winding of the power converter during an off-time period of the power switch, and transforming the second proportional voltage to a discharging current signal;
wherein the discharging current signal discharged the energy storage device, and the energy storage device produces the voltage limited signal, which is proportional to output voltage of the secondary winding of the power converter, the flip-flop further includes a second output terminal connected to the power switch to reset a second switch signal to directly control the power switch without sensing resistors, which is adapted to directly sense the switch current of the power switch, and current sensing loss.
17. The circuit of claim 16 , wherein the second transforming circuit comprises:
a second voltage-current converter, transforming the second divided voltage to a second current; and
a second current mirror circuit, mirroring the second current to a discharging current signal before discharging the energy storage device.
18. The circuit of claim 16 , wherein the voltage limited signal of energy storage device during the off-time period of the power switch is according to following equation:
Δ
V
L
-
off
=
y
×
V
O
×
B
C
×
T
off
R
y
×
N
x
wherein
y is current mirror transfer ratio;
C is capacitance of the energy storage device;
V O is an output voltage of the power converter;
B is a divided ratio the second divided voltage;
T off is time of the power converter during the off-time period;
Nx is a turns ratio of the auxiliary winding and the secondary winding; and
R y is a voltage to current conversion ratio.
19. A output regulation circuit of a power converter, the power converter including a primary winding, a secondary winding, an auxiliary winding and a power switch, comprising:
a second transforming circuit, receiving a second divided voltage from the auxiliary winding of the power converter during an off-time period of the power switch, and transforming the second proportional voltage to a discharging current signal;
an energy storage device, discharged by the discharged current signal;
a comparator, comparing a voltage limited signal of the energy storage device with a reference voltage; and
a flip-flop, including a D-input terminal, a clock-input terminal, a reset-input terminal and a second output terminal, the clock-input terminal is connected to an oscillation circuit, the D-input terminal is connected to the auxiliary winding of the power converter, the reset-input terminal is connected to an output terminal of the comparator, and the second output terminal is connected to the power switch to reset a second switch signal when the voltage limited signal is greater than the reference voltage to directly control the power switch of the power converter without sensing resistors, which is adapted to directly sense a switch current of the power switch, and current sensing loss;
wherein the voltage limited signal is proportional to an output voltage of the secondary winding of the power converter.
20. The circuit of claim 19 , wherein the second transforming circuit comprises:
a second voltage-current converter, transforming the second divided voltage to a second current; and
a second current mirror circuit, mirroring the second current to a discharging current signal before discharging the energy storage device.
21. The circuit of claim 19 , wherein the voltage limited signal of energy storage device during the off-time period of the power switch is according to following equation:
Δ
V
L
-
off
=
y
×
V
O
×
B
C
×
T
off
R
y
×
N
x
wherein
y is current mirror transfer ratio;
C is capacitance of the energy storage device;
V O is an output voltage of the power converter;
B is a divided ratio the second divided voltage;
T off is time of the power converter during the off-time period;
Nx is a turns ratio of the auxiliary winding and the secondary winding; and
R y is a voltage to current conversion ratio.
22. The circuit of claim 19 , wherein the energy storage device is an electric capacity.
23. The circuit of claim 19 , wherein the energy storage device is an inductance.Join the waitlist — get patent alerts
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